Assembled Alpha Helix Model
The Indigo alpha helix model has a mixture of alanine, lysine and serine side groups and is designed to fit the major grooves of the Indigo 17 base pair DNA model & 36 base pair DNA model with realistic steric hindrance. Available assembled only and guaranteed to have correct handendness; only $115.95.
The size of the major & minor groove in the B DNA helix is very specific since most of the important chemistry takes place there. This model has been designed to fit the major groove by taking into account the steric hindrance that is imposed on the molecule by the atoms in the DNA model. While you can physically squeeze it into the minor groove of our DNA model this would be forbidden in the real thing.
Note that poorly designed copies of our DNA model have a major groove that is more than double the size relative to to their much smaller minor groove.
The animation below from Scientific American is particularly well done. However, it doesn't mention the fact that alpha helices are attached in the major groove as anchors & are used in the process of pulling replicating DNA strands apart.